Modern telecommunication networks are commonly divided in separate parts, which are defined as RAN (Radio Access Network), core network, and backhaul network. The RAN serves UEs (User Equipments) and provides users of the UEs with communication capabilities, by providing DL data from radio base stations to the UEs and UL data from the UEs to the radio base stations. The mobile core network is a central part of the telecommunication network and provides various services to the users who are connected by the RAN, e.g. telephony and data communication. The backhaul network is the intermediate connecting network, which connects the RAN to the mobile core network.
In this description, the term “User Equipment” will be used to denote any suitable communication terminal adapted to communicate with a radio base station. A UE may be implemented as a mobile phone, a PDA (Personal Digital Assistant), a handheld computer, a laptop computer, etc. A “radio base station” may be implanted as a NodeB, an eNodeB, a repeater, etc.
With reference to FIG. 1, which is a schematic block diagram, a communication scenario will now be described according to the prior art.
A telecommunication network is illustrated in the figure and comprises a RAN where an RBS (Radio base station) 120 is present, a backhaul network where an RNC (Radio Network Controller) 100 and a core network node 140 are present, and a core network. The communication network nodes, i.e. the RBS 120, the RNC 100 and the core network node 140 are connected to each other by communication links L.
Typically, the RBS 120 comprises conventional functionality (illustrated with a box “RBS”) for downloading DL data to UEs and uploading UL data from the UEs, antennas (not shown), etc. The RNC 100 comprises conventional functionality (illustrated with a box “RNC”) for exchanging DL and UL data between a plurality of RBSs 120 and the core network node 140. The core network node 140 comprises ordinary functionality (illustrated with a box “Core”) for distributing the DL and UL data between the RNC 100 and the core network.
Traditionally, the RANs have been bottlenecks in the telecommunication networks, due to limited communication capabilities of the radio interface to the UEs. For instance, in communication systems using GSM (Groupe Special Mobile) or earlier RAN generations, the backhaul networks are often capable of providing services at higher data rates than the RANs are capable to deliver.
However, with the emergence of services, new RAN technologies have been introduced which are capable of serving the UEs with increased data rates. For instance, UMTS (Universal Mobile Telecommunication System), LTE (Long Term Evolution) and LTE Advanced systems have been defined by the 3GPP (Third Generation Partnership Project), and enables UL/DL data to be exchanged at increased data rates.
Today, the backhaul networks will not always be capable of delivering the desired data rates for communication of DL/UL data. For instance, this will be the case when backhaul links are affected by various disturbances, or when the installed backhaul capability is restricted due to aggregation of data traffic. When the users of the UEs performs services and the backhaul network is not capable of delivering the required data transfer rate, the users experience of the services may be that they are slow and/or time lagging, which may be perceived as annoying by the users.
To upgrade the communication links in the backhaul networks, for instance by installing fibre optic cables as communication links, requires a reasonable amount of resources and is time consuming and expensive.
Thus, there is a problem to devise a method for adapting RAN capabilities to variations in backhaul network characteristics.